scholarly journals Numerical Analysis and Evaluation of Large-Scale Hot Water Tanks and Pits in District Heating Systems

2020 ◽  
Author(s):  
Abdulrahman Dahash ◽  
Michele Michele Bianchi Janetti ◽  
Fabian Ochs
Keyword(s):  
Numerical Analysis ◽  
Large Scale ◽  
District Heating ◽  
Hot Water ◽  
Heating Systems ◽  
Analysis And Evaluation ◽  
District Heating Systems ◽  
Water Tanks

scholarly journals Exergy Analyses of Low-Temperature District Heating Systems With Different Sanitary Hot-Water Boosters

Entropy ◽  
2019 ◽  
Vol 21 (4) ◽  
pp. 388
Author(s):  
Poredoš ◽  
Kitanovski ◽  
Poredoš
Keyword(s):  
Low Temperature ◽  
Winter Season ◽  
District Heating ◽  
Intersection Point ◽  
Exergy Efficiency ◽  
Hot Water ◽  
Heating Systems ◽  
District Heating Systems ◽  
Different Types ◽  
Exergy Analyses

This paper presents an exergy-efficiency analysis of low-temperature district heating systems (DHSs) with different sanitary hot-water (SHW) boosters. The required temperature of the sanitary hot water (SHW) was set to 50 °C. The main objective of this study was to compare the exergy efficiencies of a DHS without a booster to DHSs with three different types of boosters, i.e., electric-, gas-boiler- and heat-pump-based, during the winter and summer seasons. To achieve this, we developed a generalized model for the calculation of the exergy efficiency of a DHS with or without the booster. The results show that during the winter season, for a very low relative share of SHW production, the DHS without the booster exhibits favorable exergy efficiencies compared to the DHSs with boosters. By increasing this share, an intersection point above 45 °C for the supply temperatures, at which the higher exergy efficiency of a DHS with a booster prevails, can be identified. In the summer season the results show that a DHS without a booster at a supply temperature above 70 °C achieves lower exergy efficiencies compared to DHSs with boosters at supply temperatures above 40 °C. The results also show that ultra-low supply and return temperatures should be avoided for the DHSs with boosters, due to higher rates of entropy generation.

scholarly journals Testing, Development and Demonstration of Large Scale Solar District Heating Systems

2015 ◽  
Vol 70 ◽  
pp. 568-573 ◽  
Author(s):  
Simon Furbo ◽  
Jianhua Fan ◽  
Bengt Perers ◽  
Weiqiang Kong ◽  
Daniel Trier ◽  
...  
Keyword(s):  
Large Scale ◽  
District Heating ◽  
Heating Systems ◽  
District Heating Systems

scholarly journals Longevity and power density of intermediate-to-deep geothermal wells in district heating applications

2021 ◽  
Vol 136 (1) ◽  
Author(s):  
Eero Hirvijoki ◽  
David Pfefferlé ◽  
Manasvi Lingam
Keyword(s):  
Heat Transfer ◽  
Power Density ◽  
Large Scale ◽  
Hot Spot ◽  
District Heating ◽  
Heat Sources ◽  
Heating Systems ◽  
District Heating Systems ◽  
Geothermal Wells ◽  
The City

AbstractThis paper assesses the potential of intermediate-to-deep geothermal wells for district heating purposes in non-hot spot regions as a means for replacing carbon-intensive heat sources. In analysing the problem of heat transfer from the bedrock to a flowing coolant in the well, we perform parameter scans to assess the longevity and power density of different-size wells and derive analytical estimates to explain salient characteristics of the well behaviour. The results are then utilized to illustrate how intermediate-to-deep geothermal wells would compare with the requirements of typical large-scale district heating systems, by using the city of Helsinki in Finland as an example.

scholarly journals Energy efficient modernization of KVG and TGV boilers

2021 ◽  
Vol 36 ◽  
pp. 22-35
Author(s):  
P. Glamazdin ◽  
D. Glamazdin
Keyword(s):  
Operating Time ◽  
Small Diameter ◽  
District Heating ◽  
Hot Water ◽  
Automation System ◽  
Convective Heating ◽  
Optimized Design ◽  
Efficient Design ◽  
Heating Systems ◽  
District Heating Systems

At present, the district heating systems of Ukrainian cities are in a critical state. They need significant modernization. This especially applies to very important components of district heating systems – heating water boilers. Unsatisfactory condition of boilers is mainly due to the obsolescence of basic equipment, including boilers. The operating time of them exceeds the passport lifetime. There ia a lack of modern automation, especially in terms of controlling operating modes. Nominal power of them exceeds the real heat loads. The range of hot water boilers used is not large. These are low-power boilers of the series NDIST, "Universal", "Energiia", "Fakel" and others, medium-power boilers of the series TVG and KVG and high-power boilers of series PTVM and KVGM. According to their prevalence, special attention should be paid to boilers of the series TVG and KVG. The series are installed on quarter boiler houses. The boilers of these series have an efficient design of the furnace volume and an optimized design of the convective part. Nevertheless, in terms of automation, gas supply and air supply systems, they no longer meet today's requirements. They are outdated comparing to the achieved level of technical solutions. The article discusses the main shortcomings of the design of boilers: insufficient durability of the gas collector in the hearth burner, small diameter of the pipes of the convective part and the use of fireclay materials in the setting of the burners. The first two shortcomings were overcome by the developers by the increase in the diameter of the pipes of convective packages and the modernization of MPIG-3 hearth burners. The third shortcoming should be overcomed by replacing the setting with a modern one during off-season repairs. Reserves for improving the energy efficiency of boilers of these series are found. To do this, it is necessary to install additional convective heating surfaces (economizers or air-heaters), replace the setting and equip the boilers with a modern automation system with cascading the burners. It allows improving efficiency up to 94...95 % and environmental performance according to the modern requirements.

scholarly journals Trends in the development of the district heating systems of Ukraine

2021 ◽  
Vol 2021 (1) ◽  
pp. 52-59
Author(s):  
V.O. Derii ◽  
Keyword(s):  
Thermal Energy ◽  
Heat Supply ◽  
District Heating ◽  
Hot Water ◽  
Low Carbon ◽  
Heating Systems ◽  
Fuel Balance ◽  
Generation Structure ◽  
District Heating Systems ◽  
Low Carbon Development

We considered trends in the development of district heating systems (DHS) in Europe and Ukraine. It was established that DHS are widely used and make a significant contribution to the heat supply of European countries. In the European Union as a whole, the share of DHS is 13%, and there are plans to increase it to 50% in 2050 with a wide use of cogeneration and renewable sources of energy, including environmental energy with using heat pumps. Ukraine is one of the countries with a high level of DHS, but, at present, there are negative trends to reducing their contribution to the total heat supply for heating and hot water supply – from 65.2% in 2014 to 52% in 2017. In several cities, DHS ceased to function at all. The main equipment of the DHS of Ukraine is physically worn out and technologically obsolete and needs to be renewed by means of wide reconstruction, modernization, and technological re-equipment. We determined factors and the level of their influence on the demand in thermal energy of DHS. It was established that the factors reducing demand have a much greater potential. We created forecasts of demand for thermal energy, fuel balance, and the structure of DHS generation by 2050. It is shown that the demand for thermal energy from DHS will decrease and reach about 35 million Gcal in 2050. To ensure the low-carbon development of Ukraine in the structure of thermal energy generation in DHS, the use of coal-fired CHPs and boilers, as well as boilers on petroleum products will be significantly reduced. The share of natural gas in the fuel balance of DHS of Ukraine will also decrease, but it will be the main fuel for the period of technological transformation of generating capacities under conditions of the low-carbon development of Ukraine. The use of technologies for the production of thermal energy from biomass, waste, environment, and electricity will gradually increase, and in 2050, using these sources will produce about 23.8 million Gcal, which is more than 60% of the total thermal energy of DHS. Keywords: district heating systems, thermal energy, factors of influence, demand, fuel balance, generation structure

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